ProcessSerialNumber psn = { 0, kCurrentProcess };
TransformProcessType(&psn, kProcessTransformToUIElementApplication);

// Create window
NSWindow* window = [[NSPanel alloc]
    initWithContentRect:frame
              styleMask:NSWindowStyleMaskTitled |
                        NSWindowStyleMaskNonactivatingPanel  // the most important mask
                backing:NSBackingStoreBuffered
                  defer:YES
                 screen:screen];

// Set window space behavior
[window setCollectionBehavior:NSWindowCollectionBehaviorCanJoinAllSpaces |
                              NSWindowCollectionBehaviorFullScreenAuxiliary];

// Set window level
[window setLevel:CGShieldingWindowLevel()];